A protocol has been approved by the NIAAA Animal Care and Use Committee. An HPLC method to separate the chiral forms of alpha-methyltryptophan has been developed. A tryptophan hydroxylase enzyme assay was used to determine the order of elution. 5OH-tryptophan, alpha-methyltryptophan, serotonin, alpha-methylserotonin, tryptophan, `-methyltryptophan can now be detected by HPLC with electrochemical detection. Pharmacokinetic studies following a bolus dose have been completed. The plasma free fraction of tryptophan and alpha-methyltryptophan have been determined. An HPLC method to separate the chiral forms of alpha-methyltryptophan is being evaluated.